<div class="wrapper">
  <label>
    autofillあり:
    <input class="autofill" type="text" autocomplete="name">
  </label>
  <label>
    autofillなし:
    <input type="text" autocomplete="name">
  </label>
</div>

.wrapper {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
}
input {
  margin-top: 2rem;
  outline: none;
  border: 3px solid red;
  &.autofill {
    &:-webkit-autofill {
      border: 3px solid green;
    }
    &:autofill {
      border: 3px solid green;
    }
  }
}